Prefabricated fireplaces, oil stoves, wood burners, gas burners and other facilities for producing heat by combustion must be equipped with ventilating pipes which channel the flow of exhaust gases away from the combustion area. The installation of such pipes often involves a sectioning and coupling operation to match and join pipe lengths of the same or different diameter.
It is difficult to make couplings in the field since, according to prior art techniques, the cut sections require end-forming operations to ensure proper interconnection. Such end-forming operations are difficult to perform in the field on even short pipe lengths. In fact, end-forming operations are difficult to perform in a factory when the pipe lenghts are great.
Hence, it is desirable to provide a coupling which may be used to join pipe sections having substantially plain, square-cut ends thereby to eliminate the need for pipe length end forming and welding operations both in the field and in the factory.